This invention relates to orientation of cans and, in particular, to the orientation of cans which are to have a textured finish which should preferably be registered with the can print, side seam or other features. Such cans may include food cans, beverage cans or aerosol cans, and may be drawn and wall-ironed (DWI), drawn and redrawn (DRD) or may have welded bodies.
One example of texturing is known as "roll-forming", in which cans are placed on a profiled mandrel and are rolled between the mandrel and a curved rail. A single revolution of the can is required to form the desired textured finish. This texturing method is described in particular in GB-A-2251197, where the mandrel is profiled with flutes so that the can body is deformed into the fluted configuration of the mandrel during the roll-forming operation. Alternatively, texturing may be achieved by forming the can between a hard profiled rail and a mandrel of elastomeric material. The textured or fluted finishes which can be obtained by such roll-forming is aesthetically pleasing but would be further enhanced if such texturing could be formed in register with print or other surface features on the can body.
GB-A-2077684 describes an apparatus for aligning bottles which have a mark in the form of a black line on the bottle neck. The apparatus uses a starwheel with spaces for the bottles, each space having a belt which engages and rotates the bottle and prevents the bottle from rotating further when the black line is detected. Such a system is not viable for registration at line speeds of the order of 1000 containers per minute and cannot align the containers with an accuracy of up to 0.5 mm+0.25 mm which is desired by present day can manufacturing lines. Furthermore, the black mark used in GB-A-2077684 would still be visible in the final product.